1. Field of the Invention
The present invention relates to a vehicle roof molding that is mounted on a roof panel by fitting it into a roof groove provided on the roof panel.
2. Background Art
A vehicle roof molding of this type is well known in a following manner. There are integrally provided a head portion for filling up at least a part of the roof groove on the roof panel and a leg portion protruding from a backside of the head portion. One pair of engaging lips protrudes from both sides of the leg portion. The pair of engaging lips has a greater thickness in a root portion and get gradually thinner toward a tip end to be elastically deformable.
In the roof molding with such a structure, the pair of engaging lips is elastically deformed to be fitted into the roof groove of the roof panel. The pair of engaging lips is fixed in the roof groove of the roof panel due to a resiliency thereof.
The conventional vehicle roof molding can be easily fitted into the roof groove of the roof panel by reducing a resiliency of elastic deformation of the pair of engaging lips, however, there arises a drawback that the roof molding is likely to get out of the roof groove of the roof panel.
In contrast, the roof molding is not easily disengaged from the roof groove of the roof panel when the resiliency of elastic deformation of the pair of engaging lips increases. However, there arises another drawback that it is difficult to fit it into the roof groove of the roof panel.
It is an object of the present invention to provide a vehicle roof molding that can easily be mounted on the roof panel by fitting it into the roof groove of the roof panel, in which the roof molding is not easily disengaged when force to pull the roof molding out of the roof groove is applied.
A vehicle roof molding according to the invention includes a head portion for filling up at least a part of the roof groove in a groove width direction, and a leg portion protruding from a backside of the head portion to be fitted in the roof groove. A pair of protruding portions is provided on both sides of the leg portion respectively. Each of the protruding portions protrudes toward a side wall of the roof groove and having a protruding end. A pair of engaging pieces, each provided in the vicinity of the protruding end respectively, includes an elastic deforming portion in a root portion thereof and a tip end.
The distance between the tip ends of the engaging pieces in a free state is set to be larger than a groove width of the roof groove.
According to the invention, the pair of the engaging pieces rotates upward to move closer to each other while the elastic deforming portion are subjected to elastic deformation, when the engaging piece is press-contacted with the side wall of the roof groove.
And the engaging piece is press-contacted with the side wall of the roof groove due to a resiliency of elastic deformation of the elastic deforming portion while the leg portion is fitted in the roof groove.
When the roof molding is mounted in the roof groove of the roof panel, the pair of engaging pieces is pushed into the roof groove while the elastic deforming portions near the tip end of the protruding portions protruding from both sides of the leg portion are subjected to elastic deformation. Thereby, one pair of engaging pieces are rotated upward to move closer to each other at the fulcrum of the elastic deforming portions and easily fitted into predetermined positions in the roof groove.
In the mounted state of the roof molding, the pair of engaging pieces is engaged under pressure against the wall faces on both sides of the roof groove, due to a resiliency of elastic deformation of the elastically deforming portions. The roof molding is held in a predetermined mounted state in the roof groove due to an engagement force (frictional force) between one pair of engaging pieces and the wall faces on both sides of the roof groove.
Also, in the mounted state of the roof molding, when pulling force acts on the roof molding, the pair of engaging pieces are prevented from sliding upward due to a frictional force of the contact portion between the pair of engaging pieces and the wall faces on both sides of the roof groove.
Therefore, when a pulling force is acted on the roof molding, the pair of engaging pieces tends to be rotated to open up at the fulcrum of the elastically deforming portions, but the opening is prevented due to the side walls of the roof groove. Thereby, the pair of engaging pieces is compressed in a direction where the engaging pieces protrude, the engaging pieces act as beams to resist the compression force, so that the pair of engaging pieces is not buckled.
Consequently, a greater frictional force is produced in the contact portion between the pair of engaging pieces and the wall faces on both sides of the roof groove than in the mounted state, and prevents the roof molding from being disengaged.
According to the invention, the protruding portion includes first protruding pieces and second protruding pieces. The first protruding pieces protrude obliquely downward from both sides of the leg portion and includes tip ends. The second protruding pieces protrude from both sides of the lower ends of the leg portion to be integrated with the tip end of the first protruding piece. A cavity portion is formed in a region surrounded by the leg portion and the first and second protruding pieces.
Accordingly, the amount of the material which constitutes the protruding portions can be saved due to the existence of the cavity portion. Further, the protruding portions can have additional elasticity and flexibility to increase the insertion performance.
According to the invention, the first protruding piece is connected integrally with the side of the leg portion via a connecting portion that is elastically deformable and thinner than the first protruding piece.
When the pair of engaging pieces with the leg portion is pushed into the roof groove, the pair of engaging pieces can be rotated to move closer to each other around the fulcrum of the thin connecting portion by elastically deforming the second protruding piece. Therefore, the pair of engaging pieces can be easily fitted into the roof groove in the roof molding mounting portion, as compared to the case in which the protruding portions have a solid and rigid structure.
According to the invention, the head portion, the leg portion, the protruding portions, the elastic deforming portions, and the pair of engaging pieces are made of olefinic thermoplastic elastomer.
Since the olefinic thermoplastic elastomer has a smaller specific gravity than the simple substance of rubber mainly composed of EDEM, or other elastomers, the roof molding with adequate elasticity and light weight can be achieved.
According to the invention, the pair of the engaging pieces and the thinner elastic deforming portions are made of a softer and more elastic material than the protruding portion.
Due to this, it is possible to retain a required resiliency and associated frictional force between the pair of engaging pieces and the wall faces on both sides of the roof groove over long time stably.
The vehicle roof molding according to the invention further comprises a cover portion formed in an outside edge of the head portion in a vehicle width direction. The cover portion is made of an elastic material softer than a material which constitutes a body portion of the head portion.
By this, when the cover portion is mounted in a state of being elastically deformed to be in contact with the roof panel, it is possible to reduce the resiliency due to an elastic deformation thereof. Therefore, even if there is some dispersion in the depth of the roof groove, or in the height of the roof molding itself, it is possible to absorb the dispersion due to the readily elastic deformation of the cover portion. Therefore, it is possible to prevent unforeseen interstice between the cover portion and the roof panel due to the dispersion.
Furthermore, it is possible to relieve the nonconformity that the roof molding is lifted upward to get out of the roof groove due to weak resiliency (reaction force) of elastic deformation of the cover portion.
According to the invention, the cover portion includes a root portion to connect the cover portion with the body portion of the head portion. The root portion is thinner than the rest of the cover portion.
Due to this, the cover portion is readily elastically deformed with a small force in the thin root portion. Therefore, even if there is some dispersion in the depth of the roof groove, or in the height of the roof molding itself, it is possible to absorb the dispersion more favorably due to the elastic deformation of the thin root portion of the cover portion. Moreover, it is possible to relieve the nonconformity that the roof molding is lifted upward to get out of the roof groove due to resiliency of elastic deformation of the thin root portion of the cover portion.
According to the invention, the head portion includes a head body portion and a cover layer provided integrally on a surface of the head body portion in a layer. The cover layer is made of a material more excellent in weather resistance and wear resistance than a material which constitutes the head body portion.
Accordingly, even when subjected to severe environments, the head main portion is protected by the cover layer excellent in weather resistance and wear resistance, making it possible to retain the intrinsic features of the head main portion over a longstanding period.